Seven members of two families who had gathered to celebrate an upcoming wedding were killed early yesterday morning when a fire, apparently started by a cigarette, swept through a sprawling, 20-room home in McLean.

Only the prospective groom, businessman Leonard L. Ragland, 36, managed to escape. His fiance, her two sons by a previous marriage, her aunt and uncle, and Ragland's mother and father perished.

Ragland, who planned to marry on Monday, told Fairfax fire investigators that he awoke about 5 a.m. to the smell of smoke, screamed to his fiance who was in the same room with him and then got out of their first-floor bedroom by smashing a window with his fist and climbing outside.

He tossed a peice of slate against an upstairs window in a futile effort to awaken his parents, officials said, then saw the fire blazing in the basement and ran barefoot to a house across the street, clad only in his sweatshirt and underwear and calling for help.

Ragland, who had just moved into his rented red brick home at 2014 Great Falls St. 12 days earlier and had never met his neighbors, telephoned firemen at 5:11 a.m. When fire trucks arrived about five minutes later, the blaze was out of control. Victims died of smoke inhalation before firemen could reach them and efforts to revive them failed, officials said.

"When we got there, it was so hot we couldn't go in right away to rescue them," said Battalion Chief Jack Akre. "It took 15, 20, 25 minutes before we had all seven located and out of the building, and by then they couldn't be saved."

The seven bodies were laid on the lawn in front of the smoldering house as Ragland, wrapped in a green blanket, walked among the rescue teams, identifying the dead. "This is my mother. This is my father," he would say, according to a firefighter.

The businessman, who ran a firm that cleaned the exteriors of large office buildings, appeared to be alternately calm and hysterical. Several times he threw back his head and cried aloud.

The death toll was the greatest in any fire in Fairfax County history, according to fire department records.

Ragland's fiancee, Virginia Wease, 35, who worked as a florist at the Giant supermarket in McLean and who moved into the house with Ragland and her two children, was found dead in the first floor bedroom. Her two sons, Kenneth Wease, 14, and James Wease, 10, were found in bed in two bedrooms on the second floor.

Ragland's parents, Leonard V. Ragland, 62, and Gertrude Ragland, 55, from Chesapeake, Va., were found in another second-floor bedroom. Wease's uncle and aunt, James A. Osteen, 55, and Gloria Osteen, 47, from Frederica, Del., were found several feet away from a sofa bed they were sleeping on in the basement.

The prospective bride and groom's families arrived Friday evening. They had all been drinking and talking with Ragland and Wease in the basement recreation room until about 3 a.m., fire officials said. They said Ragland went to bed before Wease.

Deputy Chief Fire Marshall Ronald Peck said the fire was probably caused by careless smoking in an over stuffed armchair in the basement, and said it "appears it was smouldering for a while."

Peck said the three-story house suffered an estimated $150,000 in damage. He said the fire probably smoldered for hours before Ragland was awakened. He said there were no smoke dectectors to sound a warning.

"For the price of a couple of smoke dectectors it might have been a whole different story here," Peck said. "They might have been warned before it was too late."

Relatives and friends of the victims yesterday expressed sorrow and disbelief at the news of the fatal fire.

"Dammit, this is a helluva shock," said James E. Anderson, a neighbor who lived near the elder Raglands in Chesapeake. "They've both been outstanding people." Both are retired civil servants who had worked for the Navy in Norfolk.

Virginia Wease, described by friends and relatives as an attractive slim woman with blond hair, had previously lived in the Mount Vernon area.

A neighbor there said Wease, known to her friends as "Ginger," had remained there for about a year after her divorce. He said her ex-husband would come by once a week to pick up the two children.

Her ex-husband, Kenneth M. Wease Jr., 37, a truck driver for Giant Food Corp., said word of the fire "hit me like a ton of bricks."

"I tell you it's when you sign the body release form," said Wease, grinding his hands slowly together in the kitchen of his Northern Virginia house. "That's the part that really kills you. Then I had to pick out the gravesites and caskets and you can picture them in the caskets. Boy, it's really something.

"I hope they went peacefully. If you die in your sleep, you don't feel anything, and that's the way to go," said Wease.

In late morning after the fire had been put out, officials allowed reporters to look inside the house, which Ragland rented for $750 a month. The first floor bedroom was badly charred and part of the floor had fallen into the basement.

One wing, however, was intact. In a room near the garage there was a stack of yearbooks from Groveton High School, which Virginia Wease, then Virginia Beddingfield, graduated from in the early 1960s.

In front of the house, which was built in 1948 and is set on a 4.3-acre lot bordered with tulip trees and forsythia bushes, was Ragland's Lincoln Continental Mark V and a blue van bearing the words "Mr. Kleen," the company Ragland owns and runs.

The firm, based in Sterling, cleans the exteriors of buildings, specializing in stone structures.

The house is owned by Ted Dikeman, an Arlington dentist and part-time bandleader, who said yesterday that Ragland, Wease and her two sons moved in about April 1.

"[Ragland] said he finally had found a peaceful place," Dikeman said, as he walked around the littered yard yesterday morning. "He put a basketball net on the garage last week . . . He said, with his new wife, he knew he would be happy."

Ragland had been divorced last year, fire officials said.

Virginia Wease's oldest son, Kenneth, was remembered yesterday by a Mount Vernon area grocer who employed him as "the best young boy we ever had around here. He never stopped working."

Henry Garvey, owner of the Hilltop Produce Market on Richmond Highway, said "Kenny was as good a kid as you'd want to see, honest and clean cut."

The deceased boys' father said yesterday that Kenny liked to ride trail bikes and the younger James "loved to fish."

The neighbor whom Ragland awoke shortly after 5 a.m. yesterday said he had no idea who was banging at his door.

"He [Ragland] had just moved in on the first of the month. I had thought the house was still empty," said David Young, 79, who later gave Ragland a pair of pants. "When he entered I saw blood on his hand where he had cut himself breaking the glass on the window he used to leave the house," Young said.

Officials at Fairfax Hospital said Leonard Ragland came to the emergency room briefly early yesterday morning, then left and returned several hours later.

On his second visit, doctors cleaned a cut on Ragland's right hand and prepared the wound for stitches, a hospital spokeswomen said.

But when the doctor left the treatment room, Ragland walked out ot the hospital without getting the stitches, the spokeswoman said.

"He just got up and left," she said. "He told people he didn't want to talk to anyone about what happened."